The Democratic chairman of a House panel on national security is asking Apple and Google if they keep track of how much user data is sent to China by mobile applications hosted on the companies’ platforms.

“U.S. laws permit mobile applications to collect massive amounts of personal information about their users as long as the users consent,” Massachusetts Rep. Stephen Lynch wrote in a Dec. 13 letter to Google CEO Sundar Pichai and Apple CEO Timothy Cook. “Given the pervasiveness of smartphone technology in the United States, as well as the vast amounts of information stored on those devices, foreign adversaries may be able to collect sensitive information about U.S. citizens.”

Lynch, who chairs the House Oversight Subcommittee on National Security, said the Chinese-owned video-sharing application TikTok and LGBTQ dating application Grindr were especially concerning. Kunlun, the company that owns Grindr, announced a plan to sell the application by June 2020, after the Committee on Foreign Investment in the United States (CFIUS) declared the arrangement a national security risk. CFIUS is presently investigating TikTok’s owner, Beijing ByteDance Technology Co. (DHILLON: Will Google And Apple Answer For Helping To Oppress Saudi Women?)

Lynch said the apps may represent “only a small example of how foreign adversaries might seek to exploit consumer mobile application data,” and cited an FBI finding that Russian applications represent another area of concern. 

“The FBI considers any mobile application or similar product developed in Russia … to be a potential counterintelligence threat, based on the data the product collects, its privacy and terms of use policies,” the bureau wrote in a Nov. 25 assessment of FaceApp, an application that scans users’ faces in order to virtually “age” them. The application was developed by the St. Petersburg-based Wireless Lab, a fact that consumers failed to realize before the application became widely popular in July. 

Among other questions, Lynch asked Apple and Google to describe how they determine “whether an application should be available” on their platforms, as well as whether they “require developers to disclose the country … in which their mobile will house user data.” (RELATED: Rand Paul Joins Elizabeth Warren, Ron Wyden To Question Surveillance By Credit Agencies)

Lynch isn’t the first lawmaker to express concern. Florida Republican Sen. Marco Rubio complained in an October letter to CFIUS that TikTok had “instructed its moderators to actively censor certain videos” deemed offensive by the Chinese government, adding, “the government of China is using these apps to advance their foreign policy and globally suppress freedom of speech.”